Effect of growth medium nitrogen and phosphorus on nutritional composition of Lemna minor (an alternative fish and poultry feed)

Duckweed ( Lemna minor L.) is an aquatic macrophyte and grows profoundly on the surface of polluted water reservoirs of Pakistan. The plant can be used as a potential alternative for the fish and poultry industry to meet the promptly growing demand for feed. Our study investigates the effect of varying concentrations (ppm) of nutrients like N, P, and their combination, NP on biomass production, carbohydrate, lipid, protein, and mineral (Ca, Mg, Fe, Mn & Zn) contents of L. minor . The varying concentrations of N and P substantially affected the above-stated parameters. The highest biomass yield was recorded in the 30 ppm NP tank as 172 g/m 2 day in comparison with the control tank. Higher protein, lipid, and carbohydrate contents were recorded for 30 ppm NP, 20 ppm NP, and 10 ppm NP respectively. Minerals like Ca, Mg, Fe, Mn & Zn increased in 20 ppm P and all N concentrations. The combined application of NP was more effective in boosting the protein, carbohydrate, and lipid content whereas less effective in increasing the mineral contents. A rise in the concentration of N and P showed a positive correlation with the nutritional composition of L. minor .